A conventional regenerative device that exchanges sensible heat, latent heat, and moisture between two streams of fluids can be manufactured in the form of a wheel, and can be referred to as an enthalpy wheel, an energy wheel, or a heat exchange wheel (hereinafter ‘enthalpy wheel’). Conventional enthalpy wheels are illustrated in U.S. Pat. Nos. 4,093,435, 4,924,934 and 6,155,334.
A conventional enthalpy wheel typically rotates on a shaft at fairly low speeds, for example, no more than about 40 r.p.m. The enthalpy wheel typically has a housing containing a matrix of media (capable of absorbing sensible heat) that is coated with a desiccant material (capable of absorbing moisture and thus latent as well as sensible heat). The media can be made of alternate sheets of flat and corrugated paper whose open-ended corrugations provide a multitude of parallel passages through the wheel in an axial direction. This arrangement of the corrugations facilitates the flow of fluids through the enthalpy wheel. The housing together with the media is generally rotated about the shaft by, for example, a motor.
Two fluid streams, for example, a first humidified and heated air stream and a second dry and cool air stream, can enter the enthalpy wheel along the axial direction. The first air stream flows through the enthalpy wheel from one side into an area of the media where the humidity and heat in the air stream is absorbed and retained by the media. The second air stream flows through the enthalpy wheel, generally through the opposite side from the first air stream, and into an area of the media that is usually in symmetrical relation to the area where the first stream entered the housing. As the enthalpy wheel rotates about its axis, the area of the media that has retained and absorbed the humidity and heat from the first air stream rotates to where the second air stream flows through the housing to transfer humidity and heat to the dry cool air of the second stream.